Place to write common methods containing tests

Where should the methods that contain test statements and are shared between test controllers be written to run without problems?

In a base TestCase class for testing controllers.

PHP Code:

abstract class BaseControllerTestCase extends CIUnitTestCase
{
} 


PHP Code:

class FooControllerTest extends BaseControllerTestCase
{
} 


ci-phpunit-test | CodeIgniter Testing Guide | CodeIgniter 3 to 4 Upgrade Helper